1. Field of the Invention
This invention generally relates to the acquisition and processing of images in the medical field. More particularly this invention relates to a medical imaging apparatus which contains a detector for detecting radiation emitted from an object under examination, signal forming means associated with the detector for forming an imaging signal composed of a sequence of individual image signals each representing an individual radiation image of the object under examination, a signal processor for processing the imaging signal and for forming a display signal thereof, and a display device receiving the display signal for displaying a sequence of images of the object under examination. Still more particularly, this invention relates to a medical imaging apparatus for digital radiography. Still more particularly, this invention relates to a nuclear medicine imaging apparatus and an X-ray examination apparatus.
2. Description of the Prior Art
In the brochure RR 1180 10M529 "Scintiview II" by Siemens Corporation, Iselin, N.J., there is disclosed a medical imaging apparatus which is designed to display nuclear medicine images that are acquired, for instance, from the heart of a patient. A radioisotope is supplied to the patient, and the gamma rays or X-rays emitted from the patient's body are detected by a radiation detector. The output of this detector is processed by a signal processing device and finally displayed on a screen. The medical apparatus is equipped with a recording device such as a floppy-disk system in order to store programs and patient data.
One problem associated with medical imaging is the start of the recording during the imaging process. This problem is not only relevant in X-ray and ultrasound examinations, but also in nuclear medicine. Recording could be started manually by pressing a push button. Yet, especially in high recording rates, the human delay time may cause loss of recorded information. The recording process should be started when the tracer or contrast medium enters the imaging field. A start signal given too early would result in wasted storage capacity. Since the human delay time cannot be avoided, it would be of advantage to provide electronic means which automatically provides for a start-up. At least for higher recording rates, the data recording should be improved in such a way that a start signal is given at the appropriate point of time.